1. Field of the Invention
The present invention relates to an image analysis method, apparatus and program for analyzing the movement of an object from images thereof contained in time-series image data.
2. Description of the Related Art
In general, a technique for focusing on a certain object in an image and analyzing the movement of the object is an important technique concerning images. This technique is utilized to provide TV viewers with effective synthesized images during a sports program, or to analyze the movement of players in a tennis or golf school for quantitative instruction, or to enhance the techniques of athletes.
“Multi-motion−Gymnast Form/Trajectory Display System” (Image Laboratory, vol. 9, no. 4, pp. 55-60, published by Nippon Kogyo Publisher on April 1998) is a conventional example of a technique for analyzing the movement of an object from images thereof contained in time-series image data.
In this technique, firstly, only the region (object region) including a target object is extracted from time-series image data. The object region is extracted by, for example, computing differences between frames and digitizing a region of a large difference. Further, the object region can be extracted by a chroma-key method for pre-photographing a moving object using a one-color background, and extracting the object region utilizing a difference in color, or a manual method for inputting the outline of an object extracted by a user's operation with a mouse or graphic tablet, or a method for automatically correcting the rough outline of an object input by a user, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2001-14477.
As described above, only an object is extracted from time-series image data, to thereby create object image data comprising time-series images of an object region.
After that, the time-series object image data items are superposed and synthesized in order, thereby creating a time-series image synthesized in a stroboscopic manner.
Thus, the trajectory of an object can be grasped from the display of synthesized time-series object image data. In other words, the movement of the object can be visually analyzed.
However, the image analysis method of displaying extracted time-series object image data items superposed on each other only enables viewers to see the movement of an object as successive images. This analysis is just a qualitative analysis as to how the position of the object changes, but not a quantitative analysis as to the degree of change in the position of the object.